1. Field of the Invention
The invention relates to a recorder and a method therefor, a player and a method therefor, a program and a recording medium. More specifically, it relates to a recorder and a method therefor, a player and a method therefor, a program and a recording medium, which enable a thumbnail image to be displayed in a shorter time (at a higher speed).
2. Description of the Related Art
A DVD playback device, such as a DVD (Digital Versatile Disk) recorder or a DVD video camera, often displays as a thumbnail image a representative of one or more images placed therein, which is referred to as e.g. title/chapter, for each image recording unit for the purpose of showing a user what is recorded on the data recording medium such as an optical disk with an image recorded thereon. Incidentally, the thumbnail image is an image smaller in size than its original image. In a DVD playback device like this, when a thumbnail image is displayed, the data to be utilized as a thumbnail image is read out from a moving image stream of an image data recorded on e.g. an optical disk, converted into thumbnail image data, and then displayed (See e.g. JP-A-2000-41209).
With a DVD playback device like this, in many cases two ore more thumbnail images are displayed in a screen, whereby a user can view them in a thumbnail list. In addition, when a large number of thumbnail images should be displayed, a thumbnail list containing a given number of thumbnail images is divided and displayed in pages.
The process to create a thumbnail image from a moving image stream recorded on an optical disk, which is to be executed when display of such thumbnail list is requested, takes a lot of time because the process includes reading from the optical disk and conversion to the thumbnail image.
As a countermeasure against this, many DVD playback devices operable to display a thumbnail image cache (or hold) a thumbnail image created by the process in a storage device or storage medium such as a semiconductor memory or hard disk, which are accessible at a high speed. As a result, when display of a thumbnail list is requested next time, the data reading from an optical disk and the conversion to a thumbnail image are omitted and thus display of a thumbnail image is speeded up. Otherwise, a measure of recording data after the conversion to a thumbnail image on an optical disk in itself, on which a moving image stream has been recorded and using the thumbnail image recorded on the optical disk at the time of displaying the thumbnail image is taken, thereby omitting the conversion to the thumbnail image and speeding up display of the thumbnail image.
With reference to the flow charts of FIGS. 1 and 2, a recording process in a conventional playback device will be described.
At Step S1, it is judged whether or not an instruction to start recording of video/sound data has been issued based on an operation by a user. The playback device waits until it is judged that an instruction to start the recording has been issued. When it is judged at Step S1 that an instruction to start the recording has been issued, the process proceeds to Step S2.
At Step S2, the playback device starts encoding, which starts encoding of video and sound data.
At Step S3, it is judged whether or not an instruction to terminate recording of video/sound data has been issued based on an operation by the user. The playback device waits until it is judged that an instruction to terminate the recording has been issued. When it is judged at Step S3 that an instruction to terminate the recording has been issued, the process proceeds to Step S4.
At Step S4, the playback device terminates the encoding of video and sound data.
At Step S5, the playback device writes the resultant data on a disk.
At Step S6 of FIG. 2, the playback device judges whether or not a thumbnail that should be displayed is present. When it is judged that a thumbnail that should be displayed is present, the process proceeds to Step S7.
At Step S7, the playback device judges whether or not the data of a thumbnail image has been cached. When it is judged that the thumbnail image data has not been cached, the process proceeds to Step S8. When it is judged that the thumbnail image data has been cached, the process proceeds to Step S10.
At Step S8, the playback device reads out data (video data) required to create the thumbnail image data from the disk and caches it. Then, at Step S9, the data read out by the process at Step S8 is converted into thumbnail data.
At Step S10, the playback device displays the thumbnail.
Also in the cases of DVD playback devices in reproduction, they reproduce moving pictures of two or more recording units (e.g. title/chapter). When a user makes a request to stop the reproduction, some of such DVD playback devices display a page of a thumbnail list containing a thumbnail of the recording unit (e.g. title/chapter) at the time of stopping the reproduction.
A reproduction process in a conventional playback device will be described with reference to the flow chart of FIG. 3.
At Step S31, it is judged whether or not an instruction to start reproduction of video/sound data has been issued based on an operation by a user. The playback device waits until it is judged that an instruction to start the reproduction has been issued. When it is judged at Step S31 that an instruction to start the reproduction has been issued, the process proceeds to Step S32.
At Step S32, the playback device starts decoding. Thus, decoding of video and sound data is started.
At Step S33, the playback device outputs an image and sound based on the decoded video and sound data.
At Step S34, it is judged whether or not an instruction to terminate recording of video/sound data has been issued based on an operation by the user. The playback device waits until it is judged that an instruction to terminate the recording has been issued. When it is judged at Step S34 that an instruction to terminate the recording has been issued, the process proceeds to Step S35.
At Step S35, the playback device terminates the decoding of video and sound data. After that, the process proceeds to Step S6 of FIG. 2 that has been described above.